Scientists detect gravitational waves for first time

BENGALURU: An international consortium of physicists, including those from many Indian institutions, detected gravitational waves for the first time in the world. This is considered to be an enormous achievement as the gravitational waves are very hard to detect.

“This is the scientific moonshot,” said David Reitze, LIGO Laboratory Executive Director as he announced the news. “And we have hit the moon.” This signal was produced by two colliding black holes 1.3 billion years ago. “We are opening a window on the universe,” said David Reitze.

Observing gravitational waves would enable scientists to study the universe probably not possible in any other way. Just as the news was announced, Prime Minister Narendra Modi announced through a tweet that India would build a gravitational wave detector that would form part of the Ligo network. This Rs 1,000-crore project has been waiting funding for a few years, and it was cleared by the Cabinet on Thursday evening.

There was a danger that this observatory will go to Australia, as Australian politicians was now reportedly keen on building it there. Many Indian scientists worked on the Ligo project. An observatory in India would be at the right distance from the two existing observatories in the US to calculate precisely the nature of gravitational waves. It would also give Indian astrophysicists an opportunity to work at the frontier of the new field of gravitational astronomy.

At the Inter-University Centre for Astronomy and Astrophysics in Pune, physicists celebrated the discovery and then the Modi announcement, as a big moment was replaced by a bigger moment for the Indian scientists. Many of them had developed techniques used by the Ligo observatory in the detection. The big moment for astrophysicists came on September 14 last year, when the Ligo observatory in Lousiana recorded a signal, exactly as predicted by Einstein to be when two black holes merge.

Precisely 17 milliseconds later, another observatory in Washington state in the US recorded the same signal. These two signals enabled the scientists to decode the nature of the gravitational waves precisely. The event recorded two other significant events.

It was also the first time we have seen two binary black holes merging. It is also the first evidence that binary black holes exist. It was like two stars, each thirty times the size of the sun, hitting each other at half the speed of light. This collision created gravitational waves, which travelled 1.3 billion light years to reach the earth now.